Additive Manufacturing Boosts Outlook for Optical Coatings

An exclusive supplier agreement between PPG and Flo-Optics enables the first digitally applied optical coatings and features PPG HI-GARD lens coatings. Photo courtesy of PPG.

Optical coatings are an essential part of countless products ranging from vehicle sensors to cameras to eyeglasses. Prescription laboratories treat lenses with combinations of thin layers of material for various finishes and purposes such as scratch-resistance, anti-reflective properties, blue light blocking capability and tints, making lenses more durable and functional.

Almost all lenses have at least one type of coating, with some applications requiring hundreds of thin layers. While there are many effective coating formulas, the application process can suffer from long turnaround times, product waste and human interference. Labs face challenges regarding accuracy, consistency, sustainability, and a demand for faster fulfillment.

Additive manufacturing (AM), also known as 3D printing, has the potential to completely change the way labs everywhere approach optical coatings by streamlining the process and offering endless customization options.

AM has proven its value in the manufacturing industry for short-run production and unprecedented design flexibility. The production-on-demand model allows companies to create smaller batches of highly customized products without time-consuming process alterations.

The latest AM technology, developed by Flō-Optics, adapts these benefits to optical coatings, utilizing digital printing to provide labs with precise control and unlimited coatings options. PPG is contributing its expertise in protective coatings to advance the new process and improve coatings efficiency for ophthalmic lens production.

In an industry where precision is paramount, AM’s optimized digital approach to coatings leverages cutting-edge technological and manufacturing intelligence to deliver a simplified method of production with opportunities for customization, automation, energy and waste savings, and reliable results.

Challenges in Existing Coatings Processes

A variety of methods are used to apply optical coatings including vacuum deposition, electron beam evaporation, UV spin coating and thermal dip coating. In wet processes in particular, the lens must go through multiple stages of washing, dipping and drying in a water- and energy-heavy sequence of steps.

Numerous factors can affect the coating’s adhesion; if the lens is not cleaned properly, if the environment is too humid, or if the lens is left submerged too long, the process could be unsuccessful, resulting in waste and lost revenue. Coating thickness may be inconsistent if there are even small differences in how lab technicians perform each step.

In addition, there are limitations to the available colors and types of tints that can be applied in a dip process.

Benefits of Additive Manufacturing for Optical Coatings

Using AM technology, laboratories would be able to digitally “print” any color or design onto lenses, including gradients, logos, pictures and words. The process offers precision down to the voxel level (like a pixel, but in 3D), producing dependable, repeatable results every time.

On the other hand, if there is a need for multiple lenses with slight variations, the designs are easily programmed into the AM printer’s software, allowing for mass customization that maintains production efficiency. Busy labs could handle orders with multiple variations and not be left with large amounts of unused inventory. Similar to regular printers, coatings cartridges are sealed containers that can be used over and over again, reducing the need for vats of liquids and chemicals.

The AM process requires less water and heat, making it more sustainable compared to wet processes and reduces material consumption. The increased level of control and small-batch capabilities of AM could allow laboratories to develop new types of coatings and lens products and test them quickly, reducing time to market.

Driving Innovation with Collaboration

Looking at processes through the lens of AM requires a major shift in the way manufacturers approach product design and commercialization. Although AM technology has been around for decades, its application in the ophthalmic industry has only been explored recently.

Collaboration between industry leaders can help accelerate the acceptance of new techniques like AM by adapting industry standards to new methods and machinery.

For example, PPG HI-GARD scratch-resistant coatings have a proven record of durability, chemical resistance, and optical quality. The industry knows and respects the quality of these coatings.

By partnering with Flō-Optics, PPG is helping advance step changes to the optical coatings industry, making it easier for manufacturers to incorporate AM into their operations using the coatings materials they already know and use. This partnership allows Flō-Optics to focus on solving the challenges of 3D printing onto curved lens surfaces and introduces PPG coatings to even more applications, benefiting both companies and the coatings industry as a whole.

The Smart Future of Lens Production

The optical coatings industry, already valued at more than $14 billion worldwide, is predicted to continue its expansion as more industries demand high-performance lenses that can withstand harsh conditions.

Combined with supply chain challenges and volatile markets for raw materials, increasing the efficiency of how coatings are applied is a priority for optical laboratories. AM offers a smart solution that opens the door for new product innovation and allows labs to ramp up production when needed without accumulating a surplus of inventory.

With its improved sustainability and endless design possibilities, AM has the potential to completely transform the way laboratories approach optical coatings.

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Editor’s note: This article first appeared in the January 2024 print issue of Materials Performance (MP) Magazine. Reprinted with permission.



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